This invention relates to a windshield wiper mechanism and particularly to an articulated wiper arm mechanism including a three-link parallelogram arrangement with said wiper arm for extending the wiper blade pattern.
It is known to provide an articulated wiper arm mechanism for vehicles to increase the windshield area traversed by the wiper blade. An example of such an articulated windshield wiper arm assembly is shown in U.S. Pat. No. 3,793,670 issued Feb. 26, 1974 to Riester et al. The Riester et al patent shows a wiper mechanism with a wiper arm having its fixed or inner end secured to a pivot shaft and a pivot block at its free or outer end. A control or drag arm is shown pivotally connected at its inner end to a pivot pin adjacent the pivot shaft. At its outer end the drag arm is pivotally connected on an axis parallel to but spaced from the axis of the wiper arm forming a parallelogram linkage for pivoting the blade with respect to the wiper arm as the assembly traverses its arcuate path.
The U.S. Pat. No. 2,811,736 issued Nov. 5, 1957 to E. M. Kurkechian discloses a windshield wiper having a driving arm and a secondary or control arm similar to the Riester et al articulated arm mechanism. The Kurkechian arrangement provides a greater wiping area for "wraparound" windows with more lateral travel in the latter portion of the wiping pattern.
The U.S. Pat. No. 2,821,735 issued Feb. 4, 1958 to W. E. Perkins et al discloses a single arm windshield wiper wherein a blade fitting is joined to the arm by a floating or toggle connection composed of parallel links providing an overlapping wiper blade pattern.
The U.S. Pat. No. 2,550,094 issued Apr. 24, 1951 to T. J. Smulski and the U.S. Pat. No. 4,512,056 issued Apr. 23, 1985 to M. F. Wattier discloses vehicle wiper blade control linkage arrangement forming parallelogram or articulated systems so as to modify the windshield surface wiped by the blade.